QStatusBar Class

The QStatusBar class provides a horizontal bar suitable for presenting status information. More...

Header:	#include <QStatusBar>
qmake:	QT += widgets
Inherits:	QWidget

• List of all members, including inherited members

Properties

• sizeGripEnabled : bool

Public Functions

	QStatusBar(QWidget *parent = nullptr)
virtual	~QStatusBar()
void	addPermanentWidget(QWidget *widget, int stretch = 0)
void	addWidget(QWidget *widget, int stretch = 0)
QString	currentMessage() const
int	insertPermanentWidget(int index, QWidget *widget, int stretch = 0)
int	insertWidget(int index, QWidget *widget, int stretch = 0)
bool	isSizeGripEnabled() const
void	removeWidget(QWidget *widget)
void	setSizeGripEnabled(bool)

Public Slots

void	clearMessage()
void	showMessage(const QString &message, int timeout = 0)

Signals

void	messageChanged(const QString &message)

Protected Functions

void	hideOrShow()
void	reformat()

Reimplemented Protected Functions

virtual bool	event(QEvent *e) override
virtual void	paintEvent(QPaintEvent *event) override
virtual void	resizeEvent(QResizeEvent *e) override
virtual void	showEvent(QShowEvent *) override

Detailed Description

Each status indicator falls into one of three categories:

• Temporary - briefly occupies most of the status bar. Used to explain tool tip texts or menu entries, for example.
• Normal - occupies part of the status bar and may be hidden by temporary messages. Used to display the page and line number in a word processor, for example.
• Permanent - is never hidden. Used for important mode indications, for example, some applications put a Caps Lock indicator in the status bar.

QStatusBar lets you display all three types of indicators.

Typically, a request for the status bar functionality occurs in relation to a QMainWindow object. QMainWindow provides a main application window, with a menu bar, tool bars, dock widgets and a status bar around a large central widget. The status bar can be retrieved using the QMainWindow::statusBar() function, and replaced using the QMainWindow::setStatusBar() function.

Use the showMessage() slot to display a temporary message:

void MainWindow::createStatusBar()
{
    statusBar()->showMessage(tr("Ready"));
}

To remove a temporary message, use the clearMessage() slot, or set a time limit when calling showMessage(). For example:

void MainWindow::print()
{
#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printdialog)
    QTextDocument *document = textEdit->document();
    QPrinter printer;

    QPrintDialog dlg(&printer, this);
    if (dlg.exec() != QDialog::Accepted) {
        return;
    }

    document->print(&printer);
    statusBar()->showMessage(tr("Ready"), 2000);
#endif
}

Use the currentMessage() function to retrieve the temporary message currently shown. The QStatusBar class also provide the messageChanged() signal which is emitted whenever the temporary status message changes.

Normal and Permanent messages are displayed by creating a small widget (QLabel, QProgressBar or even QToolButton) and then adding it to the status bar using the addWidget() or the addPermanentWidget() function. Use the removeWidget() function to remove such messages from the status bar.

statusBar()->addWidget(new MyReadWriteIndication);

By default QStatusBar provides a QSizeGrip in the lower-right corner. You can disable it using the setSizeGripEnabled() function. Use the isSizeGripEnabled() function to determine the current status of the size grip.

See also QMainWindow, QStatusTipEvent, GUI Design Handbook: Status Bar, and Application Example.

Member Function Documentation

QStatusBar::QStatusBar(QWidget *parent = nullptr)

Constructs a status bar with a size grip and the given parent.

See also setSizeGripEnabled().

[slot] void QStatusBar::clearMessage()

Removes any temporary message being shown.

See also currentMessage(), showMessage(), and removeWidget().

[signal] void QStatusBar::messageChanged(const QString &message)

This signal is emitted whenever the temporary status message changes. The new temporary message is passed in the message parameter which is a null-string when the message has been removed.

See also showMessage() and clearMessage().

[slot] void QStatusBar::showMessage(const QString &message, int timeout = 0)

Hides the normal status indications and displays the given message for the specified number of milli-seconds (timeout). If timeout is 0 (default), the message remains displayed until the clearMessage() slot is called or until the showMessage() slot is called again to change the message.

Note that showMessage() is called to show temporary explanations of tool tip texts, so passing a timeout of 0 is not sufficient to display a permanent message.

See also messageChanged(), currentMessage(), and clearMessage().

[virtual] QStatusBar::~QStatusBar()

Destroys this status bar and frees any allocated resources and child widgets.

void QStatusBar::addPermanentWidget(QWidget *widget, int stretch = 0)

Adds the given widget permanently to this status bar, reparenting the widget if it isn't already a child of this QStatusBar object. The stretch parameter is used to compute a suitable size for the given widget as the status bar grows and shrinks. The default stretch factor is 0, i.e giving the widget a minimum of space.

Permanently means that the widget may not be obscured by temporary messages. It is is located at the far right of the status bar.

See also insertPermanentWidget(), removeWidget(), and addWidget().

void QStatusBar::addWidget(QWidget *widget, int stretch = 0)

Adds the given widget to this status bar, reparenting the widget if it isn't already a child of this QStatusBar object. The stretch parameter is used to compute a suitable size for the given widget as the status bar grows and shrinks. The default stretch factor is 0, i.e giving the widget a minimum of space.

The widget is located to the far left of the first permanent widget (see addPermanentWidget()) and may be obscured by temporary messages.

See also insertWidget(), removeWidget(), and addPermanentWidget().

QString QStatusBar::currentMessage() const

Returns the temporary message currently shown, or an empty string if there is no such message.

See also showMessage().

[override virtual protected] bool QStatusBar::event(QEvent *e)

Reimplements: QWidget::event(QEvent *event).

[protected] void QStatusBar::hideOrShow()

Ensures that the right widgets are visible.

Used by the showMessage() and clearMessage() functions.

int QStatusBar::insertPermanentWidget(int index, QWidget *widget, int stretch = 0)

Inserts the given widget at the given index permanently to this status bar, reparenting the widget if it isn't already a child of this QStatusBar object. If index is out of range, the widget is appended (in which case it is the actual index of the widget that is returned).

The stretch parameter is used to compute a suitable size for the given widget as the status bar grows and shrinks. The default stretch factor is 0, i.e giving the widget a minimum of space.

Permanently means that the widget may not be obscured by temporary messages. It is is located at the far right of the status bar.

This function was introduced in Qt 4.2.

See also addPermanentWidget(), removeWidget(), and addWidget().

int QStatusBar::insertWidget(int index, QWidget *widget, int stretch = 0)

Inserts the given widget at the given index to this status bar, reparenting the widget if it isn't already a child of this QStatusBar object. If index is out of range, the widget is appended (in which case it is the actual index of the widget that is returned).

The stretch parameter is used to compute a suitable size for the given widget as the status bar grows and shrinks. The default stretch factor is 0, i.e giving the widget a minimum of space.

The widget is located to the far left of the first permanent widget (see addPermanentWidget()) and may be obscured by temporary messages.

This function was introduced in Qt 4.2.

See also addWidget(), removeWidget(), and addPermanentWidget().

[override virtual protected] void QStatusBar::paintEvent(QPaintEvent *event)

Reimplements: QWidget::paintEvent(QPaintEvent *event).

Shows the temporary message, if appropriate, in response to the paint event.

[protected] void QStatusBar::reformat()

Changes the status bar's appearance to account for item changes.

Special subclasses may need this function, but geometry management will usually take care of any necessary rearrangements.

void QStatusBar::removeWidget(QWidget *widget)

Removes the specified widget from the status bar.

Note: This function does not delete the widget but hides it. To add the widget again, you must call both the addWidget() and show() functions.

See also addWidget(), addPermanentWidget(), and clearMessage().

[override virtual protected] void QStatusBar::resizeEvent(QResizeEvent *e)

Reimplements: QWidget::resizeEvent(QResizeEvent *event).

[override virtual protected] void QStatusBar::showEvent(QShowEvent *)

Reimplements: QWidget::showEvent(QShowEvent *event).